This invention relates to building construction of the type where insulating panels are attached to supporting walls, ceilings or roofs, and in particular to apparatus for attaching insulating panels to a supporting surface.
A reference believed to be relevant to the present invention in U.S. Pat. No. 4,052,831 issued to Roberts et al on Oct. 11, 1977. The Roberts et al patent teaches in particular a special clip for securing insulating composite wall panels to supporting walls. As taught by the patent the use of a composite panel having a layer of foamed plastic insulating material covered by a hard rigid layer of, for example, gypsum wall board over a masonry structural wall has several distinct advantages. Such panels provide both insulation and an interior dry wall surface in a single installation step while consuming less volume than other finishing methods. The Roberts patent teaches a particular clip for retaining the panels with the intent of facilitating the installation, improving the finished appearance, and improving the insulation qualities of the finished panels. The clip comprises a sheet metal web having flanges on one edge for engaging adjacent insulation panels and a flange on the other edge for nailing or otherwise securing to the supporting wall structure.
The Roberts clip provides alignment of adjacent panels by requiring that the panel-anchoring flanges penetrate the foamed plastic layer exactly at its interface with the rigid board facing. This arrangement has several disadvantages. A hard, rigid board must be bonded to a soft insulation layer, such as foam plastic, while leaving a clearly marked interface. A variety of clips must be provided, each having a web width corresponding to the various foam layer thicknesses produced. Alignment is dependent upon the panel-anchoring flanges remaining parallel to the supporting wall and in precisely the same plane. Any warping of the flanges prevents perfect alignment of the panels. The Roberts clip also provides spacer projections on the securement flange, primarily to provide a small (0.1 inch) air space behind the panels. The spacer projections are also supposed to prevent distortion of the web and panel-anchoring flanges. But, since the clip is a one piece structure, some distortion of the flanges' position and alignment does occur when power driven nails are used. While proper spacing of the second installed of adjacent wall panels should be insured by a guide ramp and the securement flange, like spacing of the first installed panel is solely dependent upon proper insertion of the panel anchoring flange at the foam/facing interface. Securement flange distortion can cause misalignment or non-penetration due to the panel securing flange meeting the hard rigid board.
As taught in the Roberts patent and as otherwise known it is desirable to have an appreciable air space between the insulation panels and the supporting wall to prevent moisture accumulation and the growth of mold, etc. This type of wall panels are covered with a layer of aluminum foil to prevent the loss of fluorochlorocarbons and the diffusion of moisture vapor into the foam plastic insulation to help maintain exceptionally good "R" values. The aluminum foil also adds a substantial amount of insulation on its own if it is spaced from the supporting wall structure by an optimum air space of about three quarter of an inch.